1. Field of the Invention
The present invention relates to a system and method for detection and identification of laser wavelengths and, more particularly, to the use of filters having passbands which include wavelengths of interest to be identified and guardbands which ensure that radiation of no interest will be identified as being of no interest.
As used herein, the term "passband" is defined as any wavelength region of the spectrum which is permitted by an optical system to pass through it to a detector. Such passage through the system may be effected by use of a transmissive or a reflective filter. The term "guardband" is defined as a spectral region near but not including the narrow band or laser wavelength or line of interest.
2. Description of Related Art and Other Considerations
There are many applications in the laboratory and in the field where it is necessary to identify specific laser wavelengths, especially when they are mixed with adjacently propagating wavelengths. Thus, there is a need to reject wideband radiation. Conventionally, such identification of laser sources requires the use of telescope and filter combinations for filtering out all radiation but the radiation of interest.
A system, which is capable of performing this task utilizing state-of-the-art technology, requires the use of three telescope/filter/detector assemblies. Two assemblies are employed to detect the laser energy and to ascertain that it is not merely a noise pulse, and one assembly is used to detect a nearby wavelength to ensure that the source did not radiate broadband radiation. Presently, there are no known instruments which are capable of simultaneously detecting and identifying radiation from more than one laser source. An assembly, which uses current technology to produce the capabilities inherent in the invention described herein, would require the use of three telescopes for each line of radiation of interest, with two telescopes being dedicated to detection of the radiation line and one being dedicated to the guardband. The physical size, cost and complexity of such a system would indeed be very great.